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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-03-25 03:53:42 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-03-25 03:53:42 -0300
commit03dd4cb26d967f9588437b0fc9cc0e8353322bb7 (patch)
treefa581f6dc1c0596391690d1f67eceef3af8246dc /arch/arm64/kernel/entry.S
parentd4e493caf788ef44982e131ff9c786546904d934 (diff)
Linux-libre 4.5-gnu
Diffstat (limited to 'arch/arm64/kernel/entry.S')
-rw-r--r--arch/arm64/kernel/entry.S69
1 files changed, 59 insertions, 10 deletions
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 7ed3d75f6..1f7f5a2b6 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -27,6 +27,7 @@
#include <asm/cpufeature.h>
#include <asm/errno.h>
#include <asm/esr.h>
+#include <asm/irq.h>
#include <asm/thread_info.h>
#include <asm/unistd.h>
@@ -88,9 +89,12 @@
.if \el == 0
mrs x21, sp_el0
- get_thread_info tsk // Ensure MDSCR_EL1.SS is clear,
+ mov tsk, sp
+ and tsk, tsk, #~(THREAD_SIZE - 1) // Ensure MDSCR_EL1.SS is clear,
ldr x19, [tsk, #TI_FLAGS] // since we can unmask debug
disable_step_tsk x19, x20 // exceptions when scheduling.
+
+ mov x29, xzr // fp pointed to user-space
.else
add x21, sp, #S_FRAME_SIZE
.endif
@@ -108,6 +112,13 @@
.endif
/*
+ * Set sp_el0 to current thread_info.
+ */
+ .if \el == 0
+ msr sp_el0, tsk
+ .endif
+
+ /*
* Registers that may be useful after this macro is invoked:
*
* x21 - aborted SP
@@ -164,8 +175,44 @@ alternative_endif
.endm
.macro get_thread_info, rd
- mov \rd, sp
- and \rd, \rd, #~(THREAD_SIZE - 1) // top of stack
+ mrs \rd, sp_el0
+ .endm
+
+ .macro irq_stack_entry
+ mov x19, sp // preserve the original sp
+
+ /*
+ * Compare sp with the current thread_info, if the top
+ * ~(THREAD_SIZE - 1) bits match, we are on a task stack, and
+ * should switch to the irq stack.
+ */
+ and x25, x19, #~(THREAD_SIZE - 1)
+ cmp x25, tsk
+ b.ne 9998f
+
+ this_cpu_ptr irq_stack, x25, x26
+ mov x26, #IRQ_STACK_START_SP
+ add x26, x25, x26
+
+ /* switch to the irq stack */
+ mov sp, x26
+
+ /*
+ * Add a dummy stack frame, this non-standard format is fixed up
+ * by unwind_frame()
+ */
+ stp x29, x19, [sp, #-16]!
+ mov x29, sp
+
+9998:
+ .endm
+
+ /*
+ * x19 should be preserved between irq_stack_entry and
+ * irq_stack_exit.
+ */
+ .macro irq_stack_exit
+ mov sp, x19
.endm
/*
@@ -183,10 +230,11 @@ tsk .req x28 // current thread_info
* Interrupt handling.
*/
.macro irq_handler
- adrp x1, handle_arch_irq
- ldr x1, [x1, #:lo12:handle_arch_irq]
+ ldr_l x1, handle_arch_irq
mov x0, sp
+ irq_stack_entry
blr x1
+ irq_stack_exit
.endm
.text
@@ -358,10 +406,10 @@ el1_irq:
bl trace_hardirqs_off
#endif
+ get_thread_info tsk
irq_handler
#ifdef CONFIG_PREEMPT
- get_thread_info tsk
ldr w24, [tsk, #TI_PREEMPT] // get preempt count
cbnz w24, 1f // preempt count != 0
ldr x0, [tsk, #TI_FLAGS] // get flags
@@ -599,6 +647,8 @@ ENTRY(cpu_switch_to)
ldp x29, x9, [x8], #16
ldr lr, [x8]
mov sp, x9
+ and x9, x9, #~(THREAD_SIZE - 1)
+ msr sp_el0, x9
ret
ENDPROC(cpu_switch_to)
@@ -626,14 +676,14 @@ ret_fast_syscall_trace:
work_pending:
tbnz x1, #TIF_NEED_RESCHED, work_resched
/* TIF_SIGPENDING, TIF_NOTIFY_RESUME or TIF_FOREIGN_FPSTATE case */
- ldr x2, [sp, #S_PSTATE]
mov x0, sp // 'regs'
- tst x2, #PSR_MODE_MASK // user mode regs?
- b.ne no_work_pending // returning to kernel
enable_irq // enable interrupts for do_notify_resume()
bl do_notify_resume
b ret_to_user
work_resched:
+#ifdef CONFIG_TRACE_IRQFLAGS
+ bl trace_hardirqs_off // the IRQs are off here, inform the tracing code
+#endif
bl schedule
/*
@@ -645,7 +695,6 @@ ret_to_user:
and x2, x1, #_TIF_WORK_MASK
cbnz x2, work_pending
enable_step_tsk x1, x2
-no_work_pending:
kernel_exit 0
ENDPROC(ret_to_user)